I can't really say what would be best for you MM, but since I have a dodgy L5/S1 and if I had a choice of Fusion or ADR. I'd go fusion. I am way too scared of an improper placement or device failure or facet stress. Just reading about Phylly and Mark from Perth and quite a few others, I realise its complicated to get the ADR out.
I've also spoken to a few people who have had fusion at l5/s1 and they have not had much movement limitations. I emailed one lady who works on her farm all day, lifting bales of hay etc, horseriding and she's feeling great. I think the kicker is that any fusion these days must consist or removing the entire disc inserting a interbody and then using bone, preferably donor. Not excising the disc and just fusing with rods and screws will lead to a lot more pain as they disc is still leaking chemical irritant. see MartyUSA blog
Fusion surgery over.....
I'm also now a little wary of BMP from what Mark Mintzer wrote
Mimally invasive TLIF w/Hydrocision (interesting BMP data too) I honestly don't know if BMP is the problem or not. But I'd prefer if my doc didn't use it.
I'm not too concerned of adjacent disc degeneration. I wouldn't be planning to do any heavly lifting, I just want to be pain free. So if L4/L5 did degenerate, I'll deall with it then. Perhaps after another 10 years they would have improved on the ADR and you would then assess the options.
probably the hardest part of fusion is to constantly remind yourself that you are still fusing and musn't stuff up that fusion process. Its easy to forget if you are 4 months in and semi fusing and you start bending.
But as you rightly said. There is definitely no guarantees and sometimes just dumb luck can play a part.
hope you can navigate to a pain free existence Michelle.